hi
i works in a photo studio and we have two computers linked via direct LAN cable and it works fine. But the problem is, when i connect to the internet via wifi (alfa), it connects with the modem but internet dosent works. And when I disable the LAN, the internet works.

Before i used to connect both the computers via the modem and both the internet and file sharing works fine but i doubt someone steals files through the wifi. Once i found a stranger computer name my network list. After that i decided to separate wifi and LAN. And as a result the above said problem occured.

I assume 192.168.1.9 and 192.168.1.20 are assigned to your machine's LAN and WIFI interfaces. Is that correct?

If so, then your catchall route is directed back into 192.168.1.20 because of the lower metric.

IT looks like your gateway should be 192.168.1.1 for both interfaces, so that when 192.168.1.20 is alive, it sends traffic to the real gateway at 192.168.1.1 instead of back into itself which will end up going nowhere.

If these are static, then change the default gateway on 1.20 to be 1.1 instead and that will fix your issue. The other solution would be to change the metric on the interface so that 1.9 has a lower metric than 1.20. But the 1st solution is 'cleaner'.

Open up the interface in Network Connections - Change adapter settings. Pull up properties for the wifi, then properties for tcpip v4. I'll bet you have a static IP here for 192.168.1.20. Just remove the gateway. Then test it all again.